One approach to efficiently store data is to prevent the redundant copying of data that stay the same between backups. This efficient storage is achieved by dividing the data streams from data sources into segments and storing the segments and an index of identifiers to the segments on a storage device. During subsequent backup operations, the data streams are again segmented and the segments are looked up in the index to determine whether a data segment was already stored previously. If an identical segment is found, the data segment is not stored again; otherwise, the new data segment and a new index identifier are stored. Unfortunately, as the amount of data that is to be backed up increases, the number of segments (if the segments are similarly sized) and the number of index entries increases. The increase in the number of segments and index entries leads to a reduction in access performance: for writing, an incoming segment index must be compared to all the entries in the index, and for reading, a segment associated with a file must be retrieved from a larger number of segments. If the size of the segments is increased, then the number of segments decreases and therefore the number of index entries also decreases and performance can be maintained; however, the storage efficiency drops because there are not as many occurrences of the longer identical segments. It would be beneficial if access performance could be maintained without sacrificing storage efficiency.